Ignition coil

[Dcsinclair22]

How are you guys wiring your ignition coils? Mine Is pre wired to the dizzy, but the live and earth used to be earth to chassis and live to ignition (push button swith) there was nothing in between on the live (which surprises me) I'm sure there should be a ballast resistor or wire, but it worked before and since stripping the wiring and re doing it, it just won't spark, it did started once but revved right up, backfired then died, should I be taking a live from the starter motor to the ignition coil rather than the start button?  

[IanS]

If the doner was a sierra then there was no ballast resistor but a electronic module as in the link.

https://www.ebay.co.uk/itm/143733067141?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338268676&toolid=10044&customid=CjwKCAjw7c2pBhAZEiwA88pOF2ojS2FL7mbtGvbwQaZjyEMrvdMtGeXwIVuxxoIVRBbkQ_7wDVcNIhoCC1IQAvD_BwE

[Dcsinclair22]

52 minutes ago, IanS said:

If the doner was a sierra then there was no ballast resistor but a electronic module as in the link.

https://www.ebay.co.uk/itm/143733067141?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338268676&toolid=10044&customid=CjwKCAjw7c2pBhAZEiwA88pOF2ojS2FL7mbtGvbwQaZjyEMrvdMtGeXwIVuxxoIVRBbkQ_7wDVcNIhoCC1IQAvD_BwE

That would make a lot more sense but my car doesn't have anything like that, it literally had a green and black wire coming from the coil through the firewall then into the loom, +went to the start button - was earthed with a bunch of other earth's, I must be missing something as it's not sparking, maybe the +wire teed off somewhere and went to alternator or starter or a relay of some sorts 

[Sparepart]

Something in your description of where the wires go, does not sound good to me. Unfortunately you don't say which wire is + (I'm assuming black) and so green is -ve

which would match the colours used in a standard sierra loom. The way a coil works is that with ignition on, and engine not running (and points closed if you are using points) then the +ve should be live via the ignition and the -ve should run to earth but not directly, it must run to earth via the ignition module (or points). In this state the low tension windings in the coil are energized and there is magnetic energy in the coil core. When the engine is running, the ignition module (or points) suddenly disconnect the -ve from earth, this causes a suddend collapse of magnetism in the core, and the energy is dissapated in the high tension coil, giving a high voltage pulse that is used for a spark. The dissconnection only last a short while, so that the coil can recharge with energy for the next spark ... and so on. So ... if the -ve connection on your coil is directly connected to earth, there will be no interruption in the circuit and so no spark. In the Sierra loom the black comes from the ignition switch, the green runs to the electronic ignition module, which then connects the coil to earth but intermittently disconnects when a spark is required, depending on all the other inputs to the ignition module.

[Dcsinclair22]

12 minutes ago, Sparepart said:

Something in your description of where the wires go, does not sound good to me. Unfortunately you don't say which wire is + (I'm assuming black) and so green is -ve

which would match the colours used in a standard sierra loom. The way a coil works is that with ignition on, and engine not running (and points closed if you are using points) then the +ve should be live via the ignition and the -ve should run to earth but not directly, it must run to earth via the ignition module (or points). In this state the low tension windings in the coil are energized and there is magnetic energy in the coil core. When the engine is running, the ignition module (or points) suddenly disconnect the -ve from earth, this causes a suddend collapse of magnetism in the core, and the energy is dissapated in the high tension coil, giving a high voltage pulse that is used for a spark. The dissconnection only last a short while, so that the coil can recharge with energy for the next spark ... and so on. So ... if the -ve connection on your coil is directly connected to earth, there will be no interruption in the circuit and so no spark. In the Sierra loom the black comes from the ignition switch, the green runs to the electronic ignition module, which then connects the coil to earth but intermittently disconnects when a spark is required, depending on all the other inputs to the ignition module.

Thanks for that, so here's what I've got,  (and it was not wired by me, this was all the previous owners doing) the green wire goes to the - on the coil, black to + on the Coil, the ignition barrel on the car is only connected to the loom via the yellow and red wires, the blue/black and the other wire isn't connected, the ignition barrel is literally used for the steering lock, so to start the car it has a dead man switch, I turn that, then flick the 1st toggle switch which activates the fuel pump, then press the start button, but the wiring was a complete mess and I'm honestly not the most patient of people, I started off well by disconnecting each wire and labelling, but must have lost my way a bit, I cut all the wires labelling each wire 1-1 2-2 and so on, but the ends of the ignition coil wires were pretty burned up (ignition side not near the coil itself) I I decided to run 2 new wires, there is and from what I can tell never has been a control module or anything like that, I'm 97.5% sure it just had 1 wire to the bottom of the start button (going to the + on top of the coil) and the - on the coil run into a bunch of about 7 black wires that went to the chassis, I'll see if I have any more pictures 

[Dcsinclair22]

Excuse the rubbish pic, but as you look at it the - is on the left and + on the right, the - run down into the loom the to the chassis where all the earth's are and the + run into the firewall, I'll send another pic of what I was battling at the time I disconnected everything (and again this is how the car was delivered) I just wanted to tidy it up 

[Dcsinclair22]

Not sure this makes a difference but here's a pic of my dizzy, reading online some dizzy don't require a module (apparently) 

[Dcsinclair22]

OK so unsure if this is any use but just been looking through my box of spares and have came across 3 electronic modules, 3 spare distributors and a box that the new ignition was in, its a  H&H ignition (not sure if there any good) but in the instructions it does say requires 12v NON ballasted ignition from the wiring loom to the positive side of the ht coil 

[Dcsinclair22]

Sorted, it is literally the positive wire to a live feed and the negative to the clocks, god only knows why there was a black wire from the negative to the chassis,